ydb/contrib/python/aioresponses/README.rst

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aioresponses
===============================

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Aioresponses is a helper to mock/fake web requests in python aiohttp package.

For *requests* module there are a lot of packages that help us with testing (eg. *httpretty*, *responses*, *requests-mock*).

When it comes to testing asynchronous HTTP requests it is a bit harder (at least at the beginning).
The purpose of this package is to provide an easy way to test asynchronous HTTP requests.

Installing
----------

.. code:: bash

    $ pip install aioresponses

Supported versions
------------------
- Python 3.7+
- aiohttp>=3.3.0,<4.0.0

Usage
--------

To mock out HTTP request use *aioresponses* as a method decorator or as a context manager.

Response *status* code, *body*, *payload* (for json response) and *headers* can be mocked.

Supported HTTP methods: **GET**, **POST**, **PUT**, **PATCH**, **DELETE** and **OPTIONS**.

.. code:: python

    import aiohttp
    import asyncio
    from aioresponses import aioresponses

    @aioresponses()
    def test_request(mocked):
        loop = asyncio.get_event_loop()
        mocked.get('http://example.com', status=200, body='test')
        session = aiohttp.ClientSession()
        resp = loop.run_until_complete(session.get('http://example.com'))

        assert resp.status == 200
        mocked.assert_called_once_with('http://example.com')


for convenience use *payload* argument to mock out json response. Example below.

**as a context manager**

.. code:: python

    import asyncio
    import aiohttp
    from aioresponses import aioresponses

    def test_ctx():
        loop = asyncio.get_event_loop()
        session = aiohttp.ClientSession()
        with aioresponses() as m:
            m.get('http://test.example.com', payload=dict(foo='bar'))

            resp = loop.run_until_complete(session.get('http://test.example.com'))
            data = loop.run_until_complete(resp.json())

            assert dict(foo='bar') == data
            m.assert_called_once_with('http://test.example.com')

**aioresponses allows to mock out any HTTP headers**

.. code:: python

    import asyncio
    import aiohttp
    from aioresponses import aioresponses

    @aioresponses()
    def test_http_headers(m):
        loop = asyncio.get_event_loop()
        session = aiohttp.ClientSession()
        m.post(
            'http://example.com',
            payload=dict(),
            headers=dict(connection='keep-alive'),
        )

        resp = loop.run_until_complete(session.post('http://example.com'))

        # note that we pass 'connection' but get 'Connection' (capitalized)
        # under the neath `multidict` is used to work with HTTP headers
        assert resp.headers['Connection'] == 'keep-alive'
        m.assert_called_once_with('http://example.com', method='POST')

**allows to register different responses for the same url**

.. code:: python

    import asyncio
    import aiohttp
    from aioresponses import aioresponses

    @aioresponses()
    def test_multiple_responses(m):
        loop = asyncio.get_event_loop()
        session = aiohttp.ClientSession()
        m.get('http://example.com', status=500)
        m.get('http://example.com', status=200)

        resp1 = loop.run_until_complete(session.get('http://example.com'))
        resp2 = loop.run_until_complete(session.get('http://example.com'))

        assert resp1.status == 500
        assert resp2.status == 200


**Repeat response for the same url**  

E.g. for cases you want to test retrying mechanisms

.. code:: python

    import asyncio
    import aiohttp
    from aioresponses import aioresponses

    @aioresponses()
    def test_multiple_responses(m):
        loop = asyncio.get_event_loop()
        session = aiohttp.ClientSession()
        m.get('http://example.com', status=500, repeat=True)
        m.get('http://example.com', status=200)  # will not take effect

        resp1 = loop.run_until_complete(session.get('http://example.com'))
        resp2 = loop.run_until_complete(session.get('http://example.com'))

        assert resp1.status == 500
        assert resp2.status == 500


**match URLs with regular expressions**

.. code:: python

    import asyncio
    import aiohttp
    import re
    from aioresponses import aioresponses

    @aioresponses()
    def test_regexp_example(m):
        loop = asyncio.get_event_loop()
        session = aiohttp.ClientSession()
        pattern = re.compile(r'^http://example\.com/api\?foo=.*$')
        m.get(pattern, status=200)

        resp = loop.run_until_complete(session.get('http://example.com/api?foo=bar'))

        assert resp.status == 200

**allows to make redirects responses**

.. code:: python

    import asyncio
    import aiohttp
    from aioresponses import aioresponses

    @aioresponses()
    def test_redirect_example(m):
        loop = asyncio.get_event_loop()
        session = aiohttp.ClientSession()

        # absolute urls are supported
        m.get(
            'http://example.com/',
            headers={'Location': 'http://another.com/'},
            status=307
        )

        resp = loop.run_until_complete(
            session.get('http://example.com/', allow_redirects=True)
        )
        assert resp.url == 'http://another.com/'

        # and also relative
        m.get(
            'http://example.com/',
            headers={'Location': '/test'},
            status=307
        )
        resp = loop.run_until_complete(
            session.get('http://example.com/', allow_redirects=True)
        )
        assert resp.url == 'http://example.com/test'

**allows to passthrough to a specified list of servers**

.. code:: python

    import asyncio
    import aiohttp
    from aioresponses import aioresponses

    @aioresponses(passthrough=['http://backend'])
    def test_passthrough(m, test_client):
        session = aiohttp.ClientSession()
        # this will actually perform a request
        resp = loop.run_until_complete(session.get('http://backend/api'))

**also you can passthrough all requests except specified by mocking object**

.. code:: python

    import asyncio
    import aiohttp
    from aioresponses import aioresponses

    @aioresponses(passthrough_unmatched=True)
    def test_passthrough_unmatched(m, test_client):
        url = 'https://httpbin.org/get'
        m.get(url, status=200)
        session = aiohttp.ClientSession()
        # this will actually perform a request
        resp = loop.run_until_complete(session.get('http://backend/api'))
        # this will not perform a request and resp2.status will return 200
        resp2 = loop.run_until_complete(session.get(url))

**aioresponses allows to throw an exception**

.. code:: python

    import asyncio
    from aiohttp import ClientSession
    from aiohttp.http_exceptions import HttpProcessingError
    from aioresponses import aioresponses

    @aioresponses()
    def test_how_to_throw_an_exception(m, test_client):
        loop = asyncio.get_event_loop()
        session = ClientSession()
        m.get('http://example.com/api', exception=HttpProcessingError('test'))

        # calling
        # loop.run_until_complete(session.get('http://example.com/api'))
        # will throw an exception.


**aioresponses allows to use callbacks to provide dynamic responses**

.. code:: python

    import asyncio
    import aiohttp
    from aioresponses import CallbackResult, aioresponses

    def callback(url, **kwargs):
        return CallbackResult(status=418)

    @aioresponses()
    def test_callback(m, test_client):
        loop = asyncio.get_event_loop()
        session = ClientSession()
        m.get('http://example.com', callback=callback)

        resp = loop.run_until_complete(session.get('http://example.com'))

        assert resp.status == 418


**aioresponses can be used in a pytest fixture**

.. code:: python

    import pytest
    from aioresponses import aioresponses

    @pytest.fixture
    def mock_aioresponse():
        with aioresponses() as m:
            yield m


Features
--------
* Easy to mock out HTTP requests made by *aiohttp.ClientSession*


License
-------
* Free software: MIT license

Credits
-------

This package was created with Cookiecutter_ and the `audreyr/cookiecutter-pypackage`_ project template.

.. _Cookiecutter: https://github.com/audreyr/cookiecutter
.. _`audreyr/cookiecutter-pypackage`: https://github.com/audreyr/cookiecutter-pypackage